<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <div id="wrap">
        <button class="btn">替换</button>
        <div class="list">
            <li class="first">01</li>
            <li>02</li>
            <li class="mid">03</li>
            <li>04</li>
            <li>05</li>
            <li class="last">06</li>
            <!-- <li>07</li> -->
        </div>
    </div>
</body>
<script>
    // 节点的替换
    // parent.replaceChild(newNode,oldNode)   喜新厌旧 由父元素统筹 用新的节点 替换 已存在的节点    



    var list = document.getElementsByClassName("list")[0];
    var mid = document.getElementsByClassName("mid")[0];
    var btn = document.getElementsByClassName("btn")[0];


    // 点击新增按钮 创建li => 替换mid
    btn.onclick = function () {
        var li = document.createElement("li");
        // 添加属性
        li.setAttribute("class", "newLi");
        li.setAttribute("title", "hello");

        // 创建文本节点
        var text = document.createTextNode("我是新增的li");
        // console.log(text,typeof text);
        li.appendChild(text);   //把文本节点放到 li中

        console.log(li);

        // 重复替换也会报错 (The node to be replaced is not a child of this node. 被替换的节点不是当前父节点的子节点)
        if (mid) {
            list.replaceChild(li, mid);
            mid = null;
        }
    }




</script>

</html>